Method for running-in gear wheels and an agent therefor



March 1967 K. EHRLENSPlEL ETAL 3,311,555

METHOD FOR RUNNING-IN GEAR WHEELS AND AN AGENT THEREFOR Filed Sept. 27, 1962 F3 (TIP) F2(PITCH POINT) F1 (ROOT) BEFORE I LAPP'NG BEFORE "A \LAPPING INVENTORS KLAUS MICH GUSTAV NIEMANN DIETER REISTER BY low/$4:

ATTO R N EYS KLAUS EHRLENSPIEL ELS United States Patent 0 3,311,555 METHQD FOR RUNNING-IN GEAR WHEELS ANi) AN AGENT THEREFQR Klaus Ehrlenspiel and Klaus Michels, Munich, Germany,

and Gustav Nicrnann, Flemingstrasse 39, Munich, Germany, and Dieter Reister, Munich Germany; said Ehrleuspiel, said Michels, and said Reister assignors to said Niernann Filed ept. 27, 1962, Ser. No. 226,506 Claims priority, application Germany, Sept. 29, 1061, N 20,615 11 Claims. (Cl. 252--31) The present invention relates to a method for runningin gear Wheels so as to increase their flank load-bearing capacity and to provide for quieter running, as well as to minimize power losses and excessive temperatures during operation.

The invention also relates to the use of a special running-in agent or compound, to said agent proper, as well as to gear wheels, antifriction bearings, reciprocating engines, sliding guides and sliding bearings treated with said agent.

The invention further relates to the application of a novel running-in agent for metallographic polishing, swing-action lapping, and in the manufacture of bearing elements, antifriction bearings and the like.

It is well known that gear trains have to be subjected to running-in when being put into service, since the gear wheels still show some imperfections. During the first phase of the running-in there is always the danger of 9 some surface damages, for instance those usually referred to as seizing, scufling, scoring, cracking, scratching, and also excessive wear. Frequently, these running-in damages can be corrected only by expensive repairs, inasmuch as unrepaired damages substantially shorten the life span of machines. Hence, machine technology has provided for improved surface finish and has developed methods for obtaining new and better surface coatings. Until the present, abrasive agents have been employed to speed up the running-in procedure; there is no runningin without a certain wear of the material.

There exist two distinct types of running-in methods-- the mechanical method and the one utilizing running-in agents. In the mechanical methodactually a final, precision finishing process-the gear wheels are finished by hand or by means of a machine, with the aid of various machining and shaving tools. Such methods are disclosed, for example, in German Patent No. 1,003,540.

The running-in method utilizing running-in agents is known as lapping, amounting to running-in under limited load in a medium, preferably a fluid, having loose, granular abrasive substances therein. Such running-in, although relatively rapid, is characterized by uneven action over the gear tooth depth. As a result, e.g., in straight cut spur gears, bumps form on the pitch circle except if this method is carried out with a special lapping device providing compensating, corrective motions.

These known lapping methods do not provide for adaptation of the tooth flanks to displacements and distortions of their own and/or of those of the shafts which occur under the influence of the working load. A further drawback of the known lapping methods can be seen in that the lapping grain adhering to the tooth flanks can result in continuing wear during normal operation of the gear wheels.

Other running-in methods are likewise known in which no lapping grain is used, e.g., one utilizing a mixture of mineral oil and transmission lubricant or a special running-in lubricant. These methods have a drawback in that they necessitate very lengthy running-in periods and, nevertheless, provide relatively limited results.

"ice

To avoid these and other possible disadvantages, the invention provides for a special running-in composition containing components A and B, and optionally, C, in combinations A-l-B or A+B+C. This running-in composition can be used in particular for the running-in of gear wheels such as spur gears and bevel gears, as well as of hypoid and worm gears.

Component A of the inventive running-in composition is a liquid having a considerable cooling effect and low viscosity, especially water, preferably distilled Water or aqueous alcohol, or a similar organic solvent.

Component B is an agent or compound Which reacts with the metal and/or With the oxide formed on the surface thereof, hence a chemically active additive. In this capacity, use can be made of agents which are known to increase wear. In group B materials can likewise be used which are convertible, e.g., by hydrolysis, into chem ically active agents under operative conditions, in spots or areas in which a particularly heavy load bears on the gear wheel. These latent-action materials result in the gear flanks being affected only under more difiicult conditions, i.e., with higher pressure and temperatures, by splitting off of chemically active agents.

As additives, with direct chemical action, use can be made of chlorine-, sulfuror phosphorus-containing compounds, such as potassium bisulfate, calcium chloride and alkali metal salts of polyphosphoric acids, such as sodium tripolyphosphate (Na P O (ii-ammoniumphosphate, borax, potassium bichrom-ate, potassium iodate, chromates generally derived from CrO or chromic acid, sodium acetate, potassium carbonate and other rustpreventing substances, as described by E. Heyn and O. Bauer in a paper which was published in Mitteilung'en aus dem koeniglichen Materialpruefungsamt" (Reports of the Royal Ofiice for Testing Materials), Berlin 26, year 1908.

Some of these compounds are known to form protective or passivative layers on the metal surface. It is assumed that the anions of these additives react directly with the metal or with an oxide layer thereon. Of the mentioned B component, quantities corresponding to 0.1 percent by weight of A, up to maximal solubility therein, may be added, preferably corresponding to from 5 to .10 percent by weight.

Agents have a latent action, i.e., those which develop their chemically active components only in situ, may also e chlorine-, sulfuror phosphorus-containing compounds. Suitable are: colloidal sulfur, trichloromethyl-phosphonic acid [CCl PO(Ol-I) or its derivatives, e.g., its salts, esters, such as diethyl and dibutyl esters, chloroethylphosphonic acid [ClCH CH PO(OH) or its derivatives, e.g., di(chloroethyl) ester, trichloro-hydroxyethyl-phosphouic acid [CCl CI-IOHPO(OH) or its derivatives such as di(isoamyl) ester, esters of phosphorous acid, such as tri(trichloro-ethyl) phosphite [(CCl CH O) P] tri(trichloro-tertiary butyl) phosphite [[CCl C(CH O] P] zinc-dithiophosphate and tributyl trithiophosphite These agents can be added to component A in quantities of from 0.1 percent by weight up to maximal solubility therein, preferably 3 to 10 percent.

Component C which, according to the invention, is optional in the running-in compound, is an agent either soluble in A or finely dispersable therein; this agent is chemically inert with respect to the metal and increases the lubricating power of A and/ or the viscosity.

The presence of this component decreases the abrasive action to a certain degree but permits a considerably higher load to be applied to the gear wheels during their running-1n.

Component C can be chosen from the group consisting 3 of emulsifiable synthetic, mineral, vegetable or animal oils such as are known as lubricants in metal work. Suitable are also soaps and other emulsifying agents, as well as M complexes of the type the cations can also be sodium, potassium and others. These non-aqueous agents are added to the liquid component A in quantities of from 0.1 to 80%, preferably 2 to by weight.

As a viscosity increasing component C, use can be made of compounds of the group of sugars, glycerin, dextrin, water-soluble polyethylene oxide addition products having various molecular weights, triethylene glycol and polyvinyl pyrrolidone. These agents and/or their mixtures may generally be added to component A according to their solubility, in the range of from 0.5 to 95.0% by weight, preferably 25.0 to 50.0% by weight. Sugar and dextrin, due to their good solubility, can be generally used in quantities of from 0.5 to 70.0% by weight, polyvinyl pyrrolidone in 0.5 to 15.0% by weight, preferably 3.0 to 5.0% by Weight and polyvinyl alcohol in 0.5 to 40.0% by Weight, preferably 10.0 to 20.0% by Weight.

The relative proportion of components A and B and, optionally, C, depends on the effects to be achieved, as Well as on the material of which the gear wheels are made and, of course, on the activity of component B. Generally speaking, the presence of component C, especially when oils are used in this capacity, tends to reduce the chemical attack on the gear Wheel metal. However, the relative proportion of the components can be determined without difficulties by a few tests carried out by one skilled in the art.

Other objects, features and many of the attendant advantages of the invention will be readily appreciated as the same becomes better understood by reference to the following detailed description and a number of examples, when considered with the accompanying drawing, wherein FIG. 1 shows the sliding speed distribution on the tooth fianks of two meshing gear wheels;

FIG. 2 is a somewhat schematic perspective view of two teeth of a gear wheel;

FIG. 3 is an evolvent diagram of the abrasive material removal during running-in over the total tooth flank depth, using a conventional lapping agent;

FIG. 4 is a similar diagram of the removal over the total tooth flank width, using a conventional lapping agent;

FIG. 5 is an evolvent diagram similar to FIG. 3 but illustrating the abrasive material removal during runningin over the total tooth flank depth by using the inventive running-in composition (A-i-B); and

FIG. 6 is a diagram similar to FIG. 5 but showing the removal over'the total tooth flank width by using the inventive composition.

FIG. 1 shows the distribution of the rubbing or sliding speed on the tooth flanks of a gear wheel. The gears engaging each other are designated 1 and 2. The arrows 3 indicate the values of the rubbing speed at the engaging points of the tooth flanks. The line of tooth action is indicated by 7. Point 4 represents the pitch point of both gear wheels, in which the rubbing speed equals zero and only rolling occurs. The tooth flanks come momentarily into contact at points 5 and 6. Thus, FIG. 1 shows that there is a point on the tooth flanks, denoted point 4, in which no rubbing speed occurs, but only rolling. From this location, the rubbing speed increases in a linear manner both toward the tip of the tooth and toward the root.

FIG. 2 is a perspective view of two teeth of a gear wheel. FIGS. 3 and 4 show the results obtained when running-in spur gears in the gear case by means of a conventional running-in agent. The tooth flanks showed, besides surface irregularities, also alignment errors over the tooth width. The evolvent diagrams of FIGS. 3 and 5 are diagrams taken in the direction of arrow E, as seen from FIG. 2. The diagrams plotted in the direction of the flanks shown in FIGS. 4 and 6 are the F-direction diagrams of the flank widths. FIGS. 5 and 6 illustrate the results obtained by using a composition A-l-B according to the present invention.

F1 is a flank diagram line at the root, F2 that at the pitch point and F3 at the tip of the tooth flank. In FIG. 2, the pitch circle is indicated by 4a. The abrasion resulting from running-in ranges from 2 to 20 (microns). The degree of abrasion is mechanically scanned in directions F and E. The scanning results, established in these directions before the lapping or running-in, are shown in each case by broken lines while those made after the running-in are indicated by solid lines, as denoted by the legends appearing in FIGS. 3 and 4.

FIG. 3, the evolvent diagram, shows that no uniform abrasion takes place with the use of conventional runningin agents. Practically no abrasion occurs at the pitch point (F2). On the other hand, a bum develops at the pitch point and a deep recess is found at the root of the tooth (F1). FIG. 4 demonstrates that no abrasion takes place, owing to the running-in, at the pitch point so that, unlike the lines appearing at F1 and F3, no correction of thealignment error is achieved (see also Example 1).

FIGS. 5 and 6 show the results when running-in spur gears with the inventive composition (A -l-B). When comparing the respective pairs of evolvent diagrams and flank diagrams of FIGS. 3, 5 and 4, 6, respectively, it will be clear that the inventive running-in agent does not produce a bump at the pitch point. Uniform abrasion is achieved in direction of the tooth depth, coupled with a satisfactory correction of the alignment error in direction of the tooth flank, even at the pitch point (see curve P2 of FIG. 6).

The inventive process proves that the running-in hitherto accomplished in a special machine by making use of complementary movements of the axes can successfully be replaced by a running-in carried out in the very gear case in which the gear wheels are designed to operate.

An inherent advantage of the new process is that the running-in will compensate for and correct any possible irregularity and/or error resulting from assembly or from the carrying errors produced by the forces acting on the gear teeth.

To prevent corrosion, foaming, ageing, or to augment the wetting capacity, one or more additives can be used in the inventive running-in composition. Sodium nitrite, disodium phosphate, sodium chromate and vpropargyl alcohol may be mentioned as corrosion inhibiting additives. These agents'can be used in quantities of from 0.5 to 5.0% by weight, referably 1.0 to 2.0% by weight. In case of propargyl alcohol, the general range is from 0.05 to 2.0% by weight, preferably 0.1 to 0.5% by weight. Moreover, use can be made of mixtures of anion-active and non-ionic detergents, or so-called syndets (synthetic detergents), as for instance the anion-active tetrapropylene benzene sulfonate and/ or a non-ionic phenol-polyglycol ether, in quantities of from 0.1 to 5.0% by weight, preferably 0.5% by weight.

It has been found, according to the invention, that a preferred running-in agent may be composed from 94.35% distilled water, 5% sodium tripolyphosphate, 0.5% wetting agent and 0.15% propargyl alcohol, with the optional addition of 2% (ii-ammonium phosphate, all values by weight.

When using a running-in composition containing component B, accelerators can be added so that the chemical corrosion-causing component B acts more rapidly, or brings about a change in the protective layer produced by said component. Such accelerators can be, for instance, potassium perchlorate and sodium nitrite.

According to an improved, alternative process of the invention, the viscosity of the running-in compound, the relative perceptual content of the components B and C, or the circumferential velocity during the running-in can be adapted to the extent of the local abrading action of the local pressure.

The action of the components B of the running-in liquid is based on the fact that they react chemically with the material of the gears. The chemical compounds formed thereby are removed from the stressed parts of the tooth flanks under pressure or under pressure and sliding, and then again restored. This produces a chemical abrasive rocess which is combined with chemical polishing. On those parts of the gear wheel which are not in engagement and on which the layer, consisting of the basic agent and the additives of the running-in fluid, is not removed, the layer acts as a protective or passivating layer which prevents any further chemical attack.

It is thus assured that the material is removed not only at the places where sliding occurs, as is the case with lapping with mechanically acting running-in material; material is likewise removed at the points of rolling engagement of the gear tooth flanks and, particularly at the points of high pressure. When the inventive running-in composition (A +B) is used, the antifriction bearings may be protected before the start of the running-in procedure by means of a water-insoluble grease or those parts which should not be affected ought to be covered with a coat of varnish.

When using a running-in composition according to the invention, it is possible to accomplish, in a relatively short time and up to full load, the running-in of the gear tooth flanks, even when the gears have been built in for operation; this in particular answers the requirements of the motor vehicle industry.

When using the inventive process, a high-quality finish is obtained in the tooth flanks of straight-cut spur gears without the use of corrective movements. This is particularly pronounced with relation to profile shape (no bumps are formed on the pitch circle), to uniform load distribution over the entire tooth width under load, and to fine finish of the tooth flanks.

The inventive method opens especially advantageous possibilities in conjunction with spur, bevel, worm and planetary gears inasmuch as the improvement obtained here by the new running-in method in load distribution over the tooth width as well as in reduction of both local friction and temperature, can substantially increase the load capacity that can be transmitted.

With the inventive running-in method it is possible to achieve uniform load distribution over the width of the tooth flanks under full load and thus obtain quieter running and higher load capability than before, particularly under diflicult operating conditions, e.g., in case of large turbine gears having considerable tooth widths, and with large-diameter wheels having to cooperate simultaneously with several pinions.

It is furthermore possible to utilize the inventive running-in agents to run-in antifriction couplings and sliding couplings, such as roller gears, roller bearings, pistontype reciprocating machines, sliding guides and sliding bearings. The inventive running-in composition having the component B can be also used for smoothing and polishing metal parts, of the afore-mentioned kind. As soon as the desired degree of running-in is achieved, the process can be terminated by draining the running-in composition, preferably followed by rinsing with acetone and refilling with a conventional lubricant, without the need of disassembling the gearing; this is particularly advantageous in automobile gearboxes. Before the running-in, the gears are rinsed free of grease traces with the aid of solvents such as gasoline.

The invention will be further explained in a number of examples, but it should be understood that these are given by way of illustration and not of limitation and that many changes in the details can be made without departing from .the spirit of the invention. The letters used have, as mentioned before, the following meanings: A=water; B=additive with direct chemical action or one adapted to be converted in situ into a chemically active one; C=chemically inert additive suited to improve lubrication or to increase viscosity.

In carrying out the tests cited in Examples 1 to 4, the following conditions were adhered to on the gear wheel testing rig: The tested wheels were made of tempered steel of the grade 37 MnSi the flanks being preground with respect to error in flank alignment, modulus m=3.5 mm.; number of teeth 2 :21, 2 :31, tooth width=45 mm.; operating pressure angle a =20 51'. Temperature of the running-in agent=20 to 30 C. The load values specified in the following four examples are given in terms of normal tooth force in kilograms per millimeter of tooth width. PSh stands for horsepower-hour. m) stands for micrometer or Example 1 Conventional lapping agent has been used under the following conditions: 50% silicon carbide SiC (grain size 7 m.)+50% mineral oil according to SAE 90; load (normal force=kg./mm. tooth width) 5.1 kg./mm.; circumferential velocity 5.8 m./sec.; initial error in flank alignment 38 ,um.

Results: after 14 minutes of running time (work transmitted: 4 PSh), only 32% of the initial flank-alignment error, on the average; however, no improvement at pitch circle, the flanks are rough (see FIGS. 3 and 4).

Example 2 Running-in agent composed of components A and B, according to the present invention, used under the following conditions: distilled water+5% sodium tripolyphosphate+().5% wetting agent FOR (commercially available from Dr. Schnell, Munich, Germany, and containing tetrapropylenebenzene sulfonate)+0.l5% propargyl alcohol as rust inhibitor; load initially 2 kg./mm., then 3.2 kg./ mm.; circumferential velocity 1.45 m./sec.; initial error in flank alignment 25 m.

Results: after 6 hours of running time (Work transmitted: 12 PSh), only 16% of the initial flank-alignment error, on the average. Abrasion entirely uniform even at pitch circle (see FIGS. 5 and 6). Decrease of initial roughness (CLA value) CLA=0.15 m, that is, flanks as if polished or lapped.

Example 4 Running-in agent composed of component A-l-rust inhibitor INHITOL (Mannesmann), used under the following conditions: load initially 2 kg./mm., then 5.2 kg./ mm.; circumferential velocity 1.45 m./sec.; initial error in flank alignment 20 am.

Results: after 2 hours of running time (work transmitted: 11.8 PSh), only 22% of the initial flank-alignment error, on the average; however, uneven abrasion over the flank; bumps at pitch circle; slight seizing. Parallel tests were carried out on a disc type test rig as follows: discs were ground on their interfaces by means of a cup wheel. Tempered steel antifriction bearing rollers of 16 mm. diameter and 10 mm. width were clamped and pressed against the discs on both sides with a force equalling 8 kilograms. The rate of revolutions of a disc equalled 750 rpm. (v.=5.1 m./sec.). The abrasion was established on the bearing rollers, by measuring the width of the abrasion mark after 2, 7, 17, 37, and 77 minutes of operation.

Indicated hereunder, in Examples 5-14, are the abrasion volumes at the end of the tests (after 57.7-10 revolutions or 27.2 km. slide travel) at room temperature (25 to 30 C.). Material of the discs was gray cast iron of the grade GG. 22. Average roughness in sliding direction R=8.3 p.111. CLA=1.2 1m. Tensile strength of GG. 22 cast iron is 22 kilograms per mm.

l Average Runningdn Quantities in percent abrasion of Ex. agent by weight rollers after 77 minutes of operation, mm.

5 Mineral oil... 121 centistoke/Eil) G 0. 03 6 Ru lming-in Shell V 9073,5 centistoke/50" C. 0. 08

01 7 Kerosene 0. 8 Component Water-+12% Inhitol 1.12 (seizing) A+rust in hibitor. 9 Components Water+l0% sodium triphos 1. 02

A+B. phate+1% Inhitol. 10 do Water+10% sodium tripoly- 2. 3G

phosphnte+1% Inhitol. 11 do Water+% colloidal suitur+ 2. 60

1% Inhitol. 12 do Water-+25% Pentaehloro 0. 72

phenol sodium. 13.-- Components Water polyvinyl aleo- 0.31

A+B+C. liol+2.5% sodium tripolyphosphate+1% rust inhibi tor. 14 do Water+22.5% polymerized 0. 6O

ethylene oxide (molecular weight 1500)+2.5% sodium tripolyphosphnte+1% rust inhibitor+0.5% wetting agent FOR.

The results appearing in Examples 5 to 14 clearly indicate the increase of the roller Wear when using runningdn agents according to the invention. Examples 5, 6 and 7 represent the comparative tests. The abrasion values appouring in Examples 9 to 11 evidence a considerable increase When the preferred composition A+B is being used.

Seizing tests have also been carried out on a gear Wheel testing rig, which were meant to test the latentacting additives B. The following experimental conditions have been observed: profile-displaced teeth from 16 MnCr hardened, modulus m=4.5 mm.; 216 0.863; x =O.5; number of teeth Z =16, Z =24, tooth width=20 mm. Gradual load increase; torque M =0.34, 1.40, 3.55, 6.0, 9.4, 13.4, 17.4 and 24.1 mkg; 5 minutes of running time at each load value; circumferential ve locity 8.3 m./ sec. Temperature of the runningin agent= to 35 C.

Ex. Emmi-"gin Quantities in percent by weight Seizting at agent M mkg.

15.. Components Water+5% sodium tripolyphos- 1). 4

A +B. phate1% Inhitol-l-Ojfi,

wetting agent FOR. 16 .do Solution 01 Example 15+5% 17. 4

colloidal sulphur. l7 Components Solution of Example 15+45% 13. 4

A-i-B +0. polymerized ethylene oxide,

molar weight 1,500.

Examples 16 and 17 clearly show the anti-seizing eifect of both the additive B (colloidal sulphur) which is acting in situ, in case of the combination A-l-B, and the additive C, when using the combination A+B+C.

Example 18 Furthermore, tests have been conducted for investigating the smoothing effect of the inventive running-in agent. The tests have been conducted on the disc-type test rig. The abrasion mark of the steel antifriction bearing roller has been measured perpendicularly to the sliding direction with respect to roughness. In case of the indicated running-in agents, the following roughness values have been established (in ,um.):

The tests illustrate the exceptional effectiveness of the running-in agents according to the invention as compared to the known agents. Metal mirrors having an extrabright finish have a CLA value of from 0.09 to 0.015 ,um. Hence, the gear wheel flanks treated in accordance with the invention have values being comparable thereto.

Furthermore, tests were carried out on the disc test rig under the above conditions in order to show the influence of the concentration of components B and C on the abrasion.

Average abrasion of rollers after 77 minutes of operation, mm.

Example Running-in agent Quantities in percent by weight Water +01% by weight sodium tripolyphosplmte. Water +5% by weightsodium tripolyphosphate +05% wetting agent FOR +1% Inhitol. Water +1% by weight sodium 2. tripolyphosphate +05% wetting agent FOR +1% Inhitol. Water +l7.5% by weight sodium tripolypliosphate (maximum quantity solublc in water at 10 C) +0.51% by weight wetting agent FOR +1% Inhitol. Water +01% by weight horas. Water +3% by weight borax (maximum quantity soluble under operating eonditions). Water +05% by weight polyethylene oxide additive P9 (made by Badische Anilinund Soda Fabriken, Ludwigshal'en, Germany), molar weight 400+0.1% by weight sodium tripolyphosphate. Water +10% by weight P0+ 0. 25

3% by weight sodium t-ripolyphosphate. Water +20% by weight PM- 2% by weight sodium tripolyphosphate.

Components A+B. do

do do Components The above tests show clearly that, depending on the addition of component C, the abrasion can be controlled at will. At the same time, the load may be increased so as to obtain higher values of abrasion.

It should be understood, of course, that the foregoing disclosure relates only to preferred embodiments of the invention and that it is intended to cover all changes and modifications of the examples described which do not constitute departures from the spirit and scope of the invention as set forth in the appended claims.

We claim:

1. A running-in agent for metallic gears and the like, consisting essentially of a liquid selected from the group consisting of water and aqueous alcohol, having dissolved therein in an amount of from 0.1% by weight up to its maximum solubility in said liquid a compound selected from the group consisting of potassium bisulfate, calcium chloride, alkali metal salts of polyphosphoric acids, diammonium phosphate salt, borax, potassium iodate, chromic acid and alkali metal salts thereof, sodium acetate, potassium carbonate, colloidal sulfur, trichloromethyl-phosphoric acid, trichloromethyl-phosphoric acid diethyl ester, trichloromethyl-phosphoric acid dibutyl ester, chloroethyl phosphoric acid, di( :hloroethyl) ester of chloroethyl phosphoric acid, trichloro-hydroxyethylphosphoric acid, di(isoamyl) ester of trichloro-hydroxyethyl-phosphoric acid, tritertiary butyl phosphite, zinc dithiophosphate, tributyl trithiophosphite and sodium pentochlorophenol, and also containing in an amount of from 0.1 to 95.0% by weight a substance selected from the group consisting of H PO (MoO -4MoO -4H O, polyvinyl alcohol, polymerized ethylene oxide, sugar, glycerine and triethylene glycol.

2. A running-in agent for metallic gears and the like, consisting essentially of a liquid selected from the group consisting of water and aqueous alcohol, having dissolved therein in an amount of from 0.1% by weight up to its maximum solubility in said liquid a compound selected from the group consisting of potassium bisulfate, calcium chloride, alkali metal salts of polyphosphoric acids, diammonium phosphate salt, borax, chromic acid and alkali metal salts thereof, potassium iodate, sodium acetate, potassium carbonate, colloidal sulfur, trichloromethyl-phosphoric acid, trichloromethyl-phosphoric acid diethyl ester, trichloromethyl-phosphoric acid dibutyl ester, chloroethyl phosphoric acid, di(chloroethyl) ester of chloroethyl phosphoric acid, trichloro-hydroxyethyl-phosphoric acid, di(isoamyl) ester of trichloro-hydroxyethyl-phosphoric acid, tritertiary butyl phosphite, zinc dithiophosphate, tributyl trithiophosphite and sodium pentachlorophenol, and also containing between about 0.1 and 0.5% by Weight of propargyl alcohol as a rust inhibitor.

3. A running-in agent for metallic gears and the like, consisting essentially of a liquid selected from the group consisting of water and aqueous alcohol, having dissolved therein in an am-ount of from 0.1% by weight up to its maximum solubility in said liquid a compound selected from the group consisting of potassium bisulfate, calcium chloride, alkali metal salts of polyphosphoric acids, diammonium phosph-ate salt, borax, potassium iodate, chromic acid and alkali metal salts thereof, sodium acetate, potassium carbonate, colloidal sulfur, trichloromethyl-phosphoric acid, trichloromethyl-phosphoric acid diethyl ester, trichloromethyl-phosphoric acid dibutyl ester, chloroethyl phosphoric acid, di(chloroethyl) ester of chloroethyl phosphoric acid, trichlorohydroxyethylphosphoric :acid, di(isoamyl) ester of trichloro-hydroxyethyl-phosphoric acid, tritertiary butyl phosphite, zinc dithiophosphate, tributyl trithiophosphite and sodium pentachlorophenol, and also containing between about 0.1 and 0.5% by weight of tetr-apropylene benzene sulfonate as a wetting agent.

4. A running-in agent for metallic gears and the like, consisting essentially of a liquid selected from the group consisting of waterand aqueous alcohol, having dissolved therein in an amount of from 0.1% by weight up to its maximum solubility in said liquid a compound selected from the group consisting of potassium bisulfate, calcium chloride, alkali metal salts of polyphosphoric acids, diammonium phosphate salt, borax, chromic acid and alkali metal salts thereof, potassium iodate, sodium acetate, potassium carbonate, colloidal sulfur, trichloromethyl-phosphoric acid, triohloromethyl-phosphoric acid diethyl ester, trichloromethyl-phosphoric acid dibutyl ester, chloroethyl phosphoric acid, di(chloroethyl) ester of chloroethyl phosphoric acid, trichloro-hydroxyethyl-phosphoric acid, di(isoamyl) ester of trichloro-hydroxyethyl-phosphoric acid, tritertiary butyl phosphite, zinc dithiophosphate, tributyl trithiophosphite and sodium pentachlorophenol, and also containing potassium perchlorate as an accelerator for said compound.

5. A running-in agent for metallic gears and the like, consisting essentially of Water, sodium tripolyphosphate in a quantity of from 0.1% by weight to 5% by weight, and 0.15% by weight of propargyl alcohol as a rust inhibitor.

6. A running-in agent for metallic gears and the like, consisting essentially of water, 0.15% by weight of sodium tripolyphosphate and about 0.5% by weight of tetrapropylene benzene sulfonate as a wetting agent.

7. A running-in agent according to claim 6 and further containing diammonium phosphate salt in a quantity of about 2% by weight.

8. A running-in agent according to claim 1 and further containing about 01-05% by weight of propargyl alcohol as a rust inhibitor.

9. A running-in agent according to claim 1 and further containing about 01-05% by weight of tetrapropylene benzene sulfonate as a wetting agent.

10. A running-in agent according to claim 1 and further containing potassium perchlorate as an accelerator for said compound.

11. Lapping method, which comprises running-in and engine part in contact with a running-in agent consisting essentially of a liquid selected from the group consisting of water and aqueous alcohol, having dissolved therein in an amount of from 0.1% by weight up to its maximum solubility in said liquid a compound selected from the group consisting of potassium bisulfate, calcium chloride, alkali metal salts of polyphosphoric acids, diammonium phosphate salt, borax, potassium iodate, chromic acid and alkali metal salts thereof, sodium acetate, potassium carbonate, colloidal sulfur, trichloromethyl-phosphoric acid, trichloromethyl-phosphoric acid diethyl ester, trichloromethyl-phosphoric acid dibutyl ester, chloroethyl phosphoric acid, di(chloroethyl) ester of chloroethyl phosphoric acid, trichloro-hydroXyethyl-phosphoric acid, di(isoamyl) ester of trichloro-hydroXyethyl-phosphoric acid, tritertiary butylphosphite, zinc dithiophosphate, tributyl trithiophosphi-te and sodium pentachlorophenol.

References Cited by the Examiner UNITED STATES PATENTS 1,381,728 6/1921 Menard 252-11 1,913,299 6/1933 Abrams 252-31 2,007,137 7/1935 Abrams 25231 2,083,132 6/1937 Williams et al. 252-21 2,114,923 4/ 1938 Halstead 252-11 2,151,585 3/1939 Buxbaum 252-31 2,176,509 10/1939 Nuly et al 252-52X 2,346,124 4/1944 Dew 252-52 X 2,419,147 4/1947 King 23-106 2,445,901 7/ 1948 Ambrose 252-11 2,619,458 11/1952 McBride 252-25 2,780,597 2/ 1957 Williams et a1 252-25 X 2,815,560 12/1957 BuXton 252-52 X 2,932,614 4/1960 Lynch et a1. 252-32.7 2,948,588 8/1960 Baumann 23-106 2,958,659 11/1960 Brown 252-49.3 X 3,006,849 10/1961 Plemich 252-49.3 3,049,496 8/1962 Monroe et a1. 252-396 X FOREIGN PATENTS 563,728 9/1958 Canada.

340,294 12/ 1930 Great Britain.

557,755 12/ 1943 Great Britain.

604,603 7/ 1948 Great Britain.

773,820 5/1957 Great Britain.

778,468 7/1957 Great Britain.

778,818 7/1957 Great Britain.

OTHER REFERENCES Davey; Extreme Pressure Lubricants, Industrial and Engineering Chemistry, September 1950, pages 1841- Handbook of Chemistry and Physics, Charles D. Hodgman, M. 3., Chemical Rubber Publishing Co., Twenty- Seventh edition, 1943, pages 360361 relied upon.

Hughes et al.: Testing and Development of Runningin Oils for Hypoid Gears, in Scientific Lubrication, February 1961, pages 6-25.

DANIEL E. WYMAN, Primary Examiner.

R. E. HUTZ, E. W. GOLDSTEIN, P. P. GARVIN,

Assistant Examiners. 

1. A RUNNING-IN AGENT FOR METALLIC GEARS AND THE LIKE, CONSISTING ESSENTIALLY OF A LIQUID SELECTED FROM THE GROUP CONSISTING OF WATER AND AQUEOUS ALCOHOL, HAVING DISSOLVED THEREIN IN AN AMOUNT OF FROM 0.1% BY WEIGHT UP TO ITS MAXIUMUM SOLUBILITY IN SAID LIQUID A COMPOUND SELECTED FROM THE GROUP CONSISTING OF POTASSIUM BISULFATE, CALCIUM CHLORIDE, ALKALI METAL SALTS OF POLYPHOSPHORIC ACIDS, DIAMMONIUM PHOSPHATE SALT, BORAX, POTASSIUM IODATE, CHROMIC ACID AND ALKALI METAL SALTS THEREOF, SODIUM ACETATE, POTASSIUM CARBONATE, COLLOIDAL SULFUR, TRICHLOROMETHYL-PHOSPHORIC ACID, THRICHLOROMETHYL-PHOSPHORIC ACID DIETHYL ESTER, TRICHLOROMETHYL-PHOSPHORIC ACID DIBUTYL ESTER, CHLOROETHYL PHOSPHORIC ACID, DI(CHLOROETHYL) ESTER OF CHLOROETHYL PHOSPHORIC ACID, TRICHLORO-HYDROXYETHYLPHOSPHORIC ACID, DI(ISOAMYL) ESTER OF TRICHLORO-HYDROXYETHYL-PHOSPHORIC ACID, TRITERIARY BUTYL PHOSPHITE, ZINC DITHIOPHOSPHATE, TRIBUTYL TRITHIOPHOSPHITE AND SODIUM PENTOCHLOROPHENOL, AND ALSO CONTAINING IN AN AMOUNT OF FROM 0.1 TO 95.0% BY WEIGHT A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF H3PO4(MOO3)4H2O, POLYVINYL ALCOHOL, POLYMERIZED ETHYLENE OXIDE, SUGAR, GLYCERINE AND TRIETHYLENE GLYCOL. 